few questions

[zriceman]

While looking at the pre-op photos I couldn’t imagine how uncomfortable it must have been for her to smile in public.

If this event happened in the past it's "have been" rather than "Had been" correct?

As I prepare to transition from college to the next chapter in my life, I am excited to undertake the training needed to begin my professional career.

Is there a better sounding vocab to replace the words "proffessional career?"

any help is appreciated!

[paochai01]

While looking at the pre-op photos I couldn’t imagine how uncomfortable it must have been for her to smile in public.

If this event happened in the past it's "have been" rather than "Had been" correct?

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The pattern is:
must/could/should/etc. + have been
modal + have been is the right pattern regardless of the tense.

[Clark]

'Have been' is not a tense form in 'must have been'. It has nothing to do with the present/past perfect tense. This perfect infinitive form serves to express the idea of priority.